Child window state is not correctly restored after parent window is minimized and restored.

#include <QApplication>
#include <QWidget>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QWidget parent;
    QWidget child(&parent, Qt::Window);

    parent.setWindowTitle("Parent");
    child.setWindowTitle("Child");

    parent.showMaximized();
    child.showMaximized();

    parent.setWindowState(Qt::WindowMinimized);
    parent.setWindowState(Qt::WindowMaximized);

    return a.exec();
}